Chalk Stream Restoration Strategy
Chalk streams are an exceptional type of spring-fed river distinct to England and parts of France and Denmark. Although chalk exists in other parts of the world, nowhere else is there such a mass of it – the remains of an entire seafloor – exposed at the surface of the earth as rolling chalk hills, enfolding the clear-watered rivers we call chalk streams.
The English chalk downland gives rise to 283 distinct chalk streams as well as dozens of small, nameless rills and becks, comprising the vast majority of this river type to be found anywhere in the world. They are our equivalent to the Great Barrier Reef or the Okavango: a truly special natural heritage and a responsibility.
When rain falls on chalk hills it soaks down into the body of the rock and there undergoes a kind of alchemy, emerging from springs as cool, alkaline, mineral-rich water, equable in flow: the perfect properties to create a richly diverse eco-system.
Ecologically rich and biodiverse
Chalk streams in their natural condition are home to a profusion of life. Botanically they are the most biodiverse of all English rivers. For invertebrates, fish, birds and mammals, they offer a vast range of habitat niches. In Wessex they are a stronghold of our chalk-stream Atlantic salmon, now known to be genetically distinct. The upper ephemeral reaches, known as winterbournes, are global hotspots for a unique range of specialist plants and invertebrates.
Under pressure
But chalk streams are under immense pressure: they flow through one of the most urbanised, industrialised and farmed parts of the UK. Three chalk streams flow through London and there are many more in the chalk hills that surround the capital. Further afield, though many flow through more open countryside, that countryside is busily farmed, while villages or towns are sited somewhere along most chalk rivers. All these streams are impacted in one way or another by the activities of people.
We depend on chalk streams for public water supply, and have leant heavily on the resources of the underground body of water that feeds these streams. And yet every litre of water we take out of the aquifers – and we take billions and billions of litres to irrigate our crops, or run our taps – is water lost to the natural environment. Lost, that is, until we put it back. Only by the time we return water to these rivers it is no longer in the state in which we found it and has bypassed long reaches of the stream. It has passed through our sewage systems, becoming rich in nutrients and other pollutants. We may treat it, we may even treat it to a very high standard in some places, but in many others we do not. Routinely, we put back into these wonderful ecosystems water which makes them eutrophic, so that oxygen is sucked away from the river life which depends on it.
Even the water which we do not take out, which actually makes it to the underground aquifer or the stream, is unnaturally changed by human activities.
Our heavily farmed landscape exerts a huge pressure on water quality, either because rain runs off the land and along roads, accumulating harmful chemicals and nutrients along the way, or because it seeps down into the ground carrying with it the chemical fertilisers which have been applied to the land. There is now so much nitrogen in our chalk aquifers that we do not know how long it will take – even if we stopped applying nitrogen as fertiliser – for the aquifers to become clean again.
Finally, we have changed the rivers themselves, modifying them heavily over the centuries. We have used them for milling, for transport, to drive multiple agricultural and industrial revolutions. More recently, in the post-war decades, we made one of the most drastic and permanent changes of all: we dredged them. We took out the gravel river-bed – on which almost all chalk-stream life ultimately depends – and dumped it on the banks, all in an ultimately misguided attempt to drain the landscape.
Our challenge
So, we have a job ahead of us if we are to leave our wonderful chalk streams in a better state than we found them.
That is the challenge which this CaBA chalk stream restoration strategy will attempt to address – how to restore good ecological health to these unique rivers and the landscapes which support them.
CaBA is a space in which all stakeholders involved in the management, conservation and sustainable exploitation of our chalk streams can come together and agree on a way to achieve that goal. It is not always a comfortable space: NGO’s have to be pragmatic; water companies have to be idealistic; businesses, especially agriculture, have to adapt and be supported to do so: government has to listen and act.
This restoration strategy is what has come out of that discussion: an action plan which, if followed, will allow us to become proud custodians of 283 ecologically vibrant chalk streams from Dorset to Yorkshire, streams that may once more flow with a healthy flush of clean water through meandering channels over bright gravel, full of wildlife, beside which it is a pleasure to spend time and which could and should be a credit to the stewardship of our generation.
https://catchmentbasedapproach.org/learn/chalk-stream-strategy/
Download the Full Report:
Chalk streams are an exceptional type of spring-fed river distinct to England and parts of France and Denmark. Although chalk exists in other parts of the world, nowhere else is there such a mass of it – the remains of an entire seafloor – exposed at the surface of the earth as rolling chalk hills, enfolding the clear-watered rivers we call chalk streams.
The English chalk downland gives rise to 283 distinct chalk streams as well as dozens of small, nameless rills and becks, comprising the vast majority of this river type to be found anywhere in the world. They are our equivalent to the Great Barrier Reef or the Okavango: a truly special natural heritage and a responsibility.
When rain falls on chalk hills it soaks down into the body of the rock and there undergoes a kind of alchemy, emerging from springs as cool, alkaline, mineral-rich water, equable in flow: the perfect properties to create a richly diverse eco-system.
Ecologically rich and biodiverse
Chalk streams in their natural condition are home to a profusion of life. Botanically they are the most biodiverse of all English rivers. For invertebrates, fish, birds and mammals, they offer a vast range of habitat niches. In Wessex they are a stronghold of our chalk-stream Atlantic salmon, now known to be genetically distinct. The upper ephemeral reaches, known as winterbournes, are global hotspots for a unique range of specialist plants and invertebrates.
Under pressure
But chalk streams are under immense pressure: they flow through one of the most urbanised, industrialised and farmed parts of the UK. Three chalk streams flow through London and there are many more in the chalk hills that surround the capital. Further afield, though many flow through more open countryside, that countryside is busily farmed, while villages or towns are sited somewhere along most chalk rivers. All these streams are impacted in one way or another by the activities of people.
We depend on chalk streams for public water supply, and have leant heavily on the resources of the underground body of water that feeds these streams. And yet every litre of water we take out of the aquifers – and we take billions and billions of litres to irrigate our crops, or run our taps – is water lost to the natural environment. Lost, that is, until we put it back. Only by the time we return water to these rivers it is no longer in the state in which we found it and has bypassed long reaches of the stream. It has passed through our sewage systems, becoming rich in nutrients and other pollutants. We may treat it, we may even treat it to a very high standard in some places, but in many others we do not. Routinely, we put back into these wonderful ecosystems water which makes them eutrophic, so that oxygen is sucked away from the river life which depends on it.
Even the water which we do not take out, which actually makes it to the underground aquifer or the stream, is unnaturally changed by human activities.
Our heavily farmed landscape exerts a huge pressure on water quality, either because rain runs off the land and along roads, accumulating harmful chemicals and nutrients along the way, or because it seeps down into the ground carrying with it the chemical fertilisers which have been applied to the land. There is now so much nitrogen in our chalk aquifers that we do not know how long it will take – even if we stopped applying nitrogen as fertiliser – for the aquifers to become clean again.
Finally, we have changed the rivers themselves, modifying them heavily over the centuries. We have used them for milling, for transport, to drive multiple agricultural and industrial revolutions. More recently, in the post-war decades, we made one of the most drastic and permanent changes of all: we dredged them. We took out the gravel river-bed – on which almost all chalk-stream life ultimately depends – and dumped it on the banks, all in an ultimately misguided attempt to drain the landscape.
Our challenge
So, we have a job ahead of us if we are to leave our wonderful chalk streams in a better state than we found them.
That is the challenge which this CaBA chalk stream restoration strategy will attempt to address – how to restore good ecological health to these unique rivers and the landscapes which support them.
CaBA is a space in which all stakeholders involved in the management, conservation and sustainable exploitation of our chalk streams can come together and agree on a way to achieve that goal. It is not always a comfortable space: NGO’s have to be pragmatic; water companies have to be idealistic; businesses, especially agriculture, have to adapt and be supported to do so: government has to listen and act.
This restoration strategy is what has come out of that discussion: an action plan which, if followed, will allow us to become proud custodians of 283 ecologically vibrant chalk streams from Dorset to Yorkshire, streams that may once more flow with a healthy flush of clean water through meandering channels over bright gravel, full of wildlife, beside which it is a pleasure to spend time and which could and should be a credit to the stewardship of our generation.
https://catchmentbasedapproach.org/learn/chalk-stream-strategy/
Download the Full Report:

caba-csrg-strategy-main-report-final-12.10.21-low-res.pdf |
Executive Summary:

caba-csrg-strategy-exec-summary-final-11.10.21-low-res.pdf |